In this paper, the whole process flow of development, production and applications for 500 m finished rail in iron and steel enterprises is studied. The large-scale, standardized and continuous production technological system of 500 m rail is established through production process control of series of rails as well as optimization, adjustment and control of joints combining with single system quality control. The production operation modes of 100 m and 500 m rails are realized so that the goals of the shortest transfer process of production materials as well as low carbon and green for long rails have been realized in the enterprise. The control goals that sulphur content of heavy rail steel≤0.005%, ratio of equiaxed crystal for continuous casting billet reaches 42% and segregation index of manganese for rail≤1.03 are realized through deep desulfurization of refining, tundish metallurgy and narrow composition control; dimensional deviation of rail height at both ends of head and tail for 100 m rail is ensured to be ≤0.40 mm as well as differences of high-low points at the ends are ≤0.20 mm based on high precision rolling technology of rail; joint quality is effectively improved and qualified rate of joint could reach over 99% combining with rail production quality improvement and welding process optimization.

In the paper, the rock and ore are divided into three main classes and five subclasses based on iron grade and data of perforating for production in Main Mine of Bayan Obo in recent years as well as distribution rules and space coupling characteristics of contents of F and S in various types of rock and ore are summarized. The research results showed that the main occurrence minerals of element F in Main Mine of Bayan Obo were fluorite and bastnaesite as well as main occurrence minerals of element S were pyrite, pyrrhotite and galena. In terms of distribution of contents of elements F and S, it generally shows the change rule of “increasing first and then decreasing” with the increase of iron grade of ore; in terms of space distribution, elements F and S are most closely related to iron ore, space distribution range of elements F and S is gradually decreased as well as overlapping area is gradually decreased and separated, which shows the distribution characteristic of “alternate zoning with variants” with the increase of contents of F and S.

The propagation model of shock gas is established by taking the shock gas induced by instability of goaf as research background as well as the change rules of propagation rate are analyzed with the laboratory test that simulates shock gas and numerical simulation method. The study results showed that the model of flow past body of shock gas consisted of stages of uniform motion and accelerated motion; the larger the falling height of roof of goaf, the smaller the proportion of duration of uniform motion stage and the larger the proportion of duration of accelerated motion stage. The study results could provide references for prevention and treatment of shock gas disaster induced by instability of goaf.

After the separation of iron and rare earth for ore in Main and East Mines of Bayan Obo, the content of Nb₂O₅ in rare earth flotation tailings is enriched from 0.14% to 0.19%. The bulk flotation is adopted to separate easy-floating minerals in advance so as to reduce the impacts of easy-floating minerals in desilting on subsequent niobium flotation as well as the combined process of flotation and magnetic separation that bulk flotation of tailings-selective flotation of sulfur-flotation of iron-niobium flotation of iron tailings-high intensity magnetic separation of niobium concentrate is adopted to separate niobium industrially aiming at the high content of easy-floating minerals as well as close paragenesis and inclusions of niobium minerals and iron minerals. The bulk flotation is carried out under the conditions that the proportion of size fraction of -0.043 mm for grind fineness is 90%, dosage of TD-V collecting agent is 1.0 kg/t and dosage of depressor, the sodium silicate is 2.0 kg/t, sulfur flotation is carried out under the condition that dosage of butyl xanthate is 1.4 kg/t, iron flotation is carried out under the conditions that dosage of ammonium fluosilicate is 8.5 kg/t and dosage of collecting agent, the SZ fatty acid sodium salts is 0.5 kg/t as well as niobium roughing is carried out under the condition that dosages of CMC, C_5-9 and alum are 1.2 kg/t, 2.2 kg/t and 0.72 kg/t respectively. The niobium concentrate of flotation with grade of Nb₂O₅ of 2.21% is obtained by adopting the niobium flotation process of one roughing and one concentration as well as the niobium concentrate with grade of Nb₂O₅ of 4.41% and sub-niobium concentrate with grade of Nb₂O₅ of 0.96% are obtained through high intensity magnetic separation of 1.7 T so that recovery rate of niobium metal is 34.85% with the combination process of flotation and magnetic separation.

In the paper, the effects of such factors as high load operation, excessive concentration of volatile phenols and microbial poisoning on system stability are systematically analyzed aiming at the practical problem of abnormal increase of chemical oxygen demand (COD) in effluent of biological dephenolization system of Inner Mongolia Baotou Steel Qinghua Coal Chemical Industry Co., Ltd.. The COD in effluent is successfully reduced to standard level within two months so that operation pressure of subsequent advanced water treatment system is significantly relieved by adopting such comprehensive measures as reducing load of inlet, optimizing dissolved oxygen concentration, adding COD degrading bacteria and nitrifying bacteria, supplementing alkalinity to stabilize pH value, adding pulverized fuel ash into oxic tank to adsorb toxic substances as well as adjusting the strategies of sludge return and spoil disposal.

In the paper, the feasibility test of adding purchased high-silicon ore in pellet grate of Baotou Steel is carried out to analyze the changes of performances for green pellets, dry pellets and finished pellets after adding purchased high-silicon ore based on existing configuration of producing iron charge with pellet grate. The results showed that it was feasible to produce oxide pellet by adding purchased high-silicon ore in pellet grate of Baotou Steel. The performances of green pellets could meet the requirements of production processes for pellet of Baotou Steel and changes of grade of iron for oxide pellet are not great, which maintains at around 63.20% after adding 5%~10% purchased high-silicon ore in production with pellet grate. It is suggested to appropriately increase calcination temperature of pellet production in production with pellet grate of Baotou Steel under the condition that proportions of iron ore concentrate of Bayan Obo are 50% and 55% as well as adding 5%~10% purchased high-silicon ore. The compressive strength of oxide pellet produced is over 2 500 N and reduction swelling is below 20%, which could meet the requirements of blast furnace production.

In this paper, the NM1^# wear resistant steel produced by a domestic manufacturer and NM2^# wear resistant steel produced by a foreign manufacturer are selected to be compared and studied by taking rare earth wear resistant steel NM450F of Baotou Steel as the object of study as well as the corrosion resistance test is carried out with alternate immersion test equipment. The results showed that the loss mass of corrosion was 117.98 g/m² and corrosion rate was 1.64 g/(m²·h) for rare earth wear resistant steel NM450F of Baotou Steel so that its corrosion resistance was better than that of like products at home and abroad, NM1^# and NM2^# wear resistant steels. The rust layer of cross section for rare earth wear resistant steel NM450F of Baotou Steel is the thinnest and it appears to be spherical particle with uniform size to spread to matrix and tendency toward corrosion is the smallest.

In the paper, the effects of adding rare earth element Ce into Cr12MoNiNb mold steel on its inclusions and mechanical properties are studied. The morphology, size and composition of inclusions are observed and measured with scanning electron microscope, energy spectrometer and field emission electron probe. The size, quantity and precipitation law of inclusions are statistically analyzed with analysis software as well as hardness and room-temperature impact energy of samples are measured with Vickers hardness tester and impact tester. The results showed that circular or elliptical composite inclusions containing rare earth were formed in the mold steel after adding 0.002 8% of rare earth Ce and quantity of inclusions was decreased by 21.43% compared with those of the steel without adding rare earth elements so that liquid steel was purified; average size of inclusions was decreased from 3.95 μm to 3.13 μm, which was decreased by 20.76%. The hardness and room-temperature impact energy of mold steel are increased by adding rare earth Ce. Its Vickers hardness (HV) is increased from 263.0 to 283.0 and room-temperature impact energy is increased from 16.65 J to 20.05 J, which is increased by 20.42%.

In this paper, two types of online as-heat-treated pearlite rails are tempered. The optimal tempering process of two types of high-strength heat-treated rail is obtained based on the changes of mechanical properties and microstructure for the rails under different tempering temperatures. The results showed that the comprehensive mechanical properties of rail could be improved by low temperature tempering within the range of 200~350 ℃. With the increase of tempering temperature, residual stress of rail web tends to be decreased. The residual stresses of rail web for the two types of rail are 45 MPa and 32 MPa respectively with tempering at 350 ℃, which are decreased by 63.4% and 80.6% compared with those before tempering. The hardness, toughness and plasticity of tempered rail are improved with the increase of tempering temperature. The hardness is significantly increased with the improvement of plasticity and toughness. The tread hardness (HBW) of rail is increased by 13 and 8 respectively with tempering at 350 ℃ as well as the tempered rail is still with typical perlite structrure.

The effects of dimension precision of rails on stable operations of high speed train are important as well as the fluctuation of bottom width size for 60 kg/m 100 m high speed rail influences its production, delivery and use. The control methods are proposed from such four aspects as heating of billets, pass design, rolling parameters and tension of continuous mill through analyzing the main influencing factors that cause fluctuation of bottom width size for high speed rail in rolling process. The implementation effects showed that the fluctuation range of bottom width size for rail could be narrowed as well as product quality and production efficiency of rail could be improved with correct and appropriate control methods.

The industrial trial production of corrosion-resistant rail is successfully realized through strictly implementing its process system of smelting, continuous casting, heating and rolling. The comprehensive detection for microstructure, mechanical performances and corrosion resistance of trial-produced rail is carried out. The results showed that the tensile strength of rail could reach over 1 050 MPa, top surface hardness of rail head (HBW) was over 300, cross section of rail was uniform perlite and trace amount of ferritic structure as well as lamellar spacing of pearlite was reduced by 21% compared with that of traditional hot rolled U75V rail. Compared with U75V rail, the corrosion resistance of trial-produced rail for simulating coastal atmospheric environment is improved by 45.3% and corrosion resistance of simulating acid rain is improved by 54.9%, which could reach the design indexes.

In this paper, the construction technology of stay cable for Lanzhou Chaijiaxia Yellow River Bridge is discussed. The general thinking of construction is proposed, construction equipment is designed, selected, stretched and hung up as well as key points of construction and solution are determined so that the technical problems in construction of stretching and hanging up stay cable under complicated condition are solved through systematic study of construction scheme for stretching and hanging up stay cable, which could provide reference examples for the similar constructions in future.

The belt conveyer has been widely used in iron and steel enterprises. It is with such characteristics as long transportation time, strong transportation capacity, high safety and efficiency as well as low economic costs. In recent years, it is the key problem how to achieve safety and high efficiency in production process of iron and steel enterprises with the growing demands of transportation capacity for enterprises. The belt conveyer is important equipment for production and development of iron and steel enterprises as well as its safe operation has become an important link in the whole production chain. Once there is the failure of conveyer belt, it will seriously affect normal production of enterprises. In order to ensure the belt conveyer to be operated normally, corresponding preventive measures for tearing of belt should be taken by iron and steel enterprises. In this paper, the causes for tearing of belt for belt conveyer are analyzed, which could provide the basis for solving the problems of belt conveyer brought to production.

In the process of moving toward high-quality development for iron and steel industry, operating efficiency and energy consumption of steel rolling heating furnace, the core production equipment, could directly affect enterprise competitiveness. The traditional monitor mode relied on manual inspections and experience judgment so that there are such problems as lagged temperature control, low combustion efficiency and isolated data island, which could not meet the requirements of precise and intelligent productions for modern industry. In this paper, the intelligent monitoring system for steel rolling heating furnace are deeply studied, background and significances of developing the system are elaborated as well as deficiencies of traditional monitor mode are analyzed. The framework of intelligent monitoring system for steel rolling heating furnace is established based on advanced sensor technology, the Internet of things, big data analytics and artificial intelligence algorithm as well as hardware structure and software function modules of the system are introduced in detail. The remarkable effects on improving precision of temperature control for heating furnace, optimizing combustion efficiency, reducing energy consumption and ensuring production safety of the system are demonstrated through practical application cases as well as the challenges faced in process of applying the system and future development directions are discussed, which could provide the theoretical and practical references for intelligent upgrade of steel rolling industry.

The equipment in production line of rolling is with such characteristics as large size, long distance and high accuracy requirements. In the paper, the combined measurement technologies of laser tracker and total station are studied aiming at the problem that ranging accuracy of total station is relatively low. When lay the control network, such advantages as high angle measurement accuracy and long measuring distance of total station as well as high ranging accuracy of laser tracker are made full use to minimize measuring errors and complete measurement of high accuracy equipment in production line of rolling without complicated calculations.

The iron and steel industry plays a key role in the national economy and its equipment management level is closely related to the market competitiveness and sustainable development prospects of enterprises. There are such common problems as low level of intelligence for equipment management, poor operating environment and processes are not clear in iron and steel enterprises so that traditional equipment management modes cannot meet the requirements of high efficiency, precision and intelligent management for modern iron and steel enterprises. The equipment management level and production efficiency are further improved, operating costs are reduced as well as comprehensive competitiveness of enterprise is enhanced by carrying out the life cycle management of equipment that focuses on digital construction, applications of new technologies as well as green and sustainable development.

In the article, it is discussed the effects of drying time, prepared sizes, preparation time, stirring means and storage time of samples on measurement results of caking index which are not specified in the national standard GB/T 5447—2014. Such two types of frequently-used bitumite, coking coal and gas coal are selected for experimental study. The study results showed that the effects of drying time, particle size and preparation time of samples on measurement results of G value were the most significant, the effects of analysis link and storage time of samples on measurement results of G value took second place, while the effects of stirring means on measurement results of G value were minimum. The specified control conditions of related influencing factors are given through experiments so as to achieve the goal of improving the accuracy of measurement results for caking index of bitumite.

The samples are prepared with fused bead method, contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in fluorite are determined with wavelength dispersion X-ray fluorescence spectrometry as well as effects of such factors as type of flux, dilution ratio, weighing sample, melting temperature and melting time on determination results are analyzed so that optimal experimental conditions are determined. Meanwhile, the working curves of each element are drawn using standard samples and self-made control samples as well as correlation coefficients all reach over 0.999. The precision experiment showed that the relative standard deviation (RSD, n=10) of determination results for contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in fluorite was 0.23%~4.80%, the accuracy experiment showed that the difference values of measured values, standard values and chemical analysis values for contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in standard sample of fluorite and control sample of wet chemical analysis were within the range of allowable deviation for the methods of GB/T 5195.5—2017, GB/T 5195.6—2006, GB/T 5195.1—2017 and GB/T 5195.8—2006. The method is with shorter analysis process, higher sensitivity and certain promotion and application value compared with wet chemical analysis.

In this paper, it is introduced the determination of oxygen content in lanthanum-iron alloy with the pulse melting-infrared absorption method. The preparation method and optimal analysis conditions are determined by studying the preparation methods of sample as well as analyzing the effects of power, weighing sample and flux on determination results of oxygen content. The standard deviation is less than 5% and recovery rate is 95%~105% for this method, so it is with good precision and accuracy.

In the paper, it is elaborated comprehensively integrate idea of green development in procurement activities, drive green development of procurement by means of digital intelligence tools, promote green manufacturing with green procurement, build brand of green digital intelligence supply chain, guide and drive green, low carbon and circular synergetic development of upstream and downstream enterprises as well as accelerate green and low carbon transformation development of the entire chain for iron and steel enterprises from the perspective of modern supply chain, which could play a role of demonstration and leading for state-owned enterprises to achieve the national strategic goal of “carbon peaking and carbon neutrality” as well as provide strong supports for accelerating establishment of world-class enterprise.

In the paper, the diversified application practices of such modern intelligent technologies as the Internet of things, big data, unmanned aerial vehicle and artificial intelligence in safety production management are deeply discussed based on their advantages. It is with such advantages as improving working efficiency, reducing accident risks, providing intelligent decision supports and saving costs to apply the intelligent technologies in safety production. As a result, the level of safety production management in enterprises is improved significantly with the intelligent technologies, which is helpful to optimize safety production management system. This paper is aimed to provide the application practice cases for related fields and promote the intelligent upgrade of safety production management.